Embodiments of the inventive concept described herein relate to a retro-reflective sheet and a method for manufacturing the same, and more particularly, to a retro-reflective body that may enhance visibility by improving light reflecting efficiency in a colored area at night, and a method for manufacturing the same.
A retro-reflective sheet is a reflective body that directly reflects incident light including a light condensing layer and a reflective layer in an incident direction. The retro-reflective sheet generally has a sheet shape, and is machined to have a desired pattern on a surface of a body of an attachment object to be attached to a road sign or a selected part of a uniform of a fireperson or the like through thermal fusion or sewing, thereby enhancing visibility such that it is easily displayed at a place, of which a surrounding environment is dark. Accordingly, if the retro-reflective sheet is attached to clothing of a person, who works on a road or at a dangerous place, such as a garbage collector, a fireperson, a policeperson, a laborer in a factory, a construction field worker, and a safety person in the field, protection and safety of the wearer may be effectively guaranteed by allowing the surrounding people to firmly identify a location of the wearer.
Further, the retro-reflective sheet has a stripe pattern shape that alternately formed with reflective areas in which a color area reflects light and thus may secure visibility even at night. The reflective area has a structure in which a light collecting layer is formed by attaching beads onto the reflective layer, on which metal such as aluminum is deposited, and the colored area includes a colored layer, on which an organic binder including a colored pigment having fluorescent or light accumulating characteristics is applied.
The retro-reflective sheet according to the related art is disclosed in Korean Patent No. 10-1206376 (entitled ‘Method for Manufacturing Retro-reflective Sheet and’).
The retro-reflective sheet according to the related art includes a base, a bonding layer formed on the base, a colored layer formed such that a non-reflective area is thicker than a reflective area so that a surface of the bonding layer is uneven and having a fluorescent function or a light accumulating function, or both of a fluorescent function and a light accumulating function, a reflective layer formed in the uneven part of the reflective area of the surface of the colored layer, and a light condensing layer formed on the reflective layer such that a plurality of beads are arranged.
In this case, the colored layer may selectively include a fluorescent pigment and a fluorescent material including a fluorescent pigment, or a light accumulating pigment and a light accumulating material including a light accumulating pigment, or may include a fluorescent material and a light accumulating material together to emit light through a fluorescence operation at night or emitting light that has been accumulated by absorbing light during the day or in the interior of a building, at night, thereby enhancing visibility at night or in a dark place. Further, if the colored layer includes a fluorescent material and a light accumulating material together, it may perform a fluorescence operation and a light accumulating operation at the same time. In this case, the light emitted from the colored layer has colors such as red (R), green (G), and blue (B) according to the fluorescent material or the light accumulating material.
A light reflecting member including the reflective layer and the light condensing layer is formed at the uneven part on the surface of the colored layer to reflect light input to the reflective area at night to the outside.
In this case, the light reflecting member including the reflective layer and the light condensing layer is formed in the uneven part formed in the reflective area on the colored layer so as not to be stepped from a surface of the colored layer of the non-reflective area so that the light reflecting member is prevented from being delaminated from the base.
In this case, the quantity of light reflected from the reflective area is approximately 500 cd/lux*m2, and the quantity of light reflected from the colored area is not more than 30 cd/lux*m2) Accordingly, when the widths of the reflective layer and the colored layer are the same, the quantity of light reflected from the retro-reflective sheet is approximately 265 cd/lux*m2.
Accordingly, because the retro-reflective sheet according to the related art reflects a small quantity of light on the colored area except for the reflective area, it decreases visibility.